> The MOC is just a code generation tool, it's about as objectionable as bison.
I think you've missed the whole point. No one cares about implementation details. The critical aspect is that Qt imposes the use of a superset of C++ which includes keywords such as signals and slots. Technically it's not even C++, but a language which has its own unique keywords, concurrency model, object ownership and life cycle, etc.
This is overly dramatic. The "keywords" are just macros. If you don't want an additional preprocessor to generate code in a separate .cpp file from these macros, you can use https://github.com/woboq/verdigris
The concurrency model, object ownership and life cycle you are mentioning are not part of C++, those are just conventions in specific C++ user groups - Qt code compiles plain and simple with pretty much every conformant C++ compiler and that makes it as much C++ as anything else.
I think you've missed the whole point. No one cares about implementation details. The critical aspect is that Qt imposes the use of a superset of C++ which includes keywords such as signals and slots. Technically it's not even C++, but a language which has its own unique keywords, concurrency model, object ownership and life cycle, etc.